JP4681098B2 - Video projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention uses a light emitting diode.Video projectorAbout.
[0002]
[Prior art]
A light emitting diode (hereinafter referred to as an LED) generally has advantages such as long life, high efficiency, high G resistance, and monochromatic light emission compared to bubble lamps such as xenon and metal halide. For this reason, in recent years, there has been a trend of shifting from bubble lamps to LEDs as light emitting sources in many lighting applications.
[0003]
However, in general, an LED has a small amount of light emitted from a unit element. Therefore, in applications in the field of illumination that requires a relatively large amount of light, for example, as shown in the specifications of Japanese Patent Application Nos. 59-162964 and 9-69803, a large number of LED elements are used. The amount of light required is ensured by arranging and arranging on one plane or a curved surface.
[0004]
By the way, in a video projection illumination device such as a video projector, the projection illumination light source device is required to have high luminance as well as absolute light quantity. Therefore, for example, as shown in the above specification, the LED elements that are light emitting sources are gathered together so as to have as high an integration density as possible, and the light beams emitted from each LED element are combined with one convex condenser lens and one The image display element is projected and illuminated using an optical system including a field lens.
Further, in order to secure a large amount of light required, a large number of LED elements are distributed on a plane substantially orthogonal to the optical axis of the illumination light of the projection illumination light source device.
[0005]
[Problems to be solved by the invention]
However, if the LED elements are arranged as described above, the area of the light emitting portion increases in proportion to the number of LED elements even if the required large amount of light can be secured. Couldn't be raised. Particularly, it has been impossible to efficiently project and illuminate a small image display element having a diagonal size of about 1 inch, and to efficiently reflect or transmit the reflected or transmitted light from the image display element to the projection lens.
[0006]
  An object of the present invention is to use a high-efficiency light-emitting diode that can obtain a high-luminance projection illumination light beam and can efficiently project and illuminate a small image display element.Video projectorIs to provide.
[0007]
[Means for Solving the Problems]
  In order to solve the above problems, the invention described in claim 1 is, for example, as shown in FIG.
  A planar light source (for example, planar light source 11) in which a plurality of light emitting diodes (for example, LED elements 11a ...) are discretely distributed in the plane 18, and an optical axis are arranged so as to be orthogonal to the plane. Condensing lens (for example, convex condenser lens 12)Condensing system AWhen,Projection illumination light source device 10When,
An image display element 16 for providing image information to a projection illumination light beam emitted from the projection illumination light source device;
A projection lens 17 for projecting a projection illumination light beam to which image information is given onto the screen 19,
A video projector comprising: a polarization beam splitter 15 that irradiates the projection illumination light beam onto the image display element and causes the projection illumination light beam received by the video display element to enter the projection lens.Because
  The length in the direction orthogonal to the optical axis direction of the light emission of the planar light source is longer than the aperture of the projection lens,
  The direction of the optical axis of the light emission of the light emitting diode is from the optical axis of the condenser lens.lightIt is inclined at an angle determined depending on the distance to the diode with respect to the optical axis direction of the condenser lens toward the outside of the condenser lens.
[0008]
According to the first aspect of the present invention, the light axis of the light emitting diode is focused with respect to the optical axis direction of the light collecting lens at an angle determined depending on the distance from the light axis of the light collecting lens to the light emitting diode. It is tilted toward the outside of the lens. In such an arrangement, when the emitted light from a plurality of light emitting diodes is combined into one light flux by the condenser lens and the molded lens, the light flux of the light flux of the light emitting diode is smaller than that in the case where the optical axis of the light emitting diode is parallel to the optical axis of the condenser lens. The spread can be further suppressed, and a light beam suitable for projection illumination with a small divergence angle can be obtained. That is, the angle divergence can be suppressed during the light collection by the condenser lens by tilting the light-emitting diode optical axis at the outer peripheral portion of the planar light source to the outside.
Thus, by obtaining the projection illumination light beam with reduced angle divergence, vignetting loss due to the finite size of the entire optical system, such as when the projection illumination light beam hits the lens frame or the like, can be suppressed. Therefore, for example, when the projection illumination light source device of the present invention is applied as a light source of a video projector, the emitted light from the light emitting diode can be effectively guided to a projection lens that projects an image.
Therefore, it is possible to increase the brightness of the projection illumination light beam, and to obtain a projection illumination light source device that can efficiently project and project even a small image display element.
[0009]
In addition, since the projection illumination light source device of the present invention uses a light emitting diode as a light source, it provides characteristics such as long life, high efficiency, and high G resistance as compared with a conventional case where a bubble lamp is used. be able to. Therefore, by using the projection illumination light source device of the present invention, a maintenance-free and long-life image projector can be obtained.
[0010]
  The invention described in claim 2 is described in claim 1.Video projectorFor example, as shown in FIG.
  Radiation direction adjusting means (for example, small-diameter convex lens 21b...) For adjusting the radiation direction of the light emitting diode (for example, LED element 21a...)
  An optical axis direction of light emission of at least a part of the light emitting diodes is inclined by the radiation direction adjusting means.
[0011]
According to the second aspect of the present invention, since the radiation direction adjusting means for adjusting the radiation direction from the light emitting diode is provided, the radiation light incident on the condensing lens of the condensing system is the same as in the first aspect. Can tilt. Therefore, an effect similar to that of the first aspect can be obtained.
[0012]
In addition, as a radiation direction adjustment means, it is good also as a structure which arrange | positions a convex lens separately, for example at the front-end | tip of each said light emitting diode.
In this case, when arranging the convex lens, in order to adjust the direction of emission of the light emitting diode as desired, for example, the central axis of the light emitting diode and the central axis of the convex lens are translated and shifted by a predetermined amount. The optical axis of the light emitting diode and the optical axis of the convex lens may be rotated and arranged at a predetermined angle in front of the light emitting diode. In addition, a convex lens may be arranged by combining parallel movement and rotation so that radiation from the light emitting diode is in a desired direction.
Further, as the radiation direction adjusting means, an optical element other than a convex lens may be used.
[0013]
  The invention described in claim 3 is described in claim 1 or 2.Video projectorFor example, as shown in FIG.
  Radiation divergence depression means (for example, small-diameter convex lens 21b...) That narrows the full angle of radiation divergence of the light emitting diode is provided.
[0014]
According to the invention described in claim 3, since the same effect as that of claim 1 or 2 can be obtained and the radiation divergence depression means for narrowing the total radiation divergence angle of the light emitting diode is provided, the light emitting diode is further provided. Can be collected with reduced angular divergence.
As a result, even when a light emitting diode having a somewhat large radiation divergence full angle is originally used, the light can be condensed while suppressing the angle divergence, and the selection range of the light emitting diode applicable to the present invention can be expanded.
[0015]
Note that, as the radiant divergence angle means, for example, if a convex lens is arranged in front of each light emitting diode, the radiant divergence full angle can be preferably narrowed.
In this case, since the direction of radiation can be adjusted by adjusting the arrangement of the convex lenses as desired, it can also serve as the radiation direction adjusting means. Therefore, it is preferable because the number of parts can be reduced and the configuration can be simplified.
Moreover, it is preferable to adjust the radiation direction and the light collection degree of the radiated light from the light emitting diode as desired by appropriately selecting a convex lens according to the application and purpose.
Further, as the radiation divergence depression means, an optical element other than a convex lens may be used.
[0016]
  The invention according to claim 4 is, for example, as shown in FIG.Video projectorIn
  The light emitting diodeitselfThe total angle of radiation divergence of is within 8 °.
[0017]
According to the invention described in claim 4, since the same effect as in claims 1 to 3 can be obtained, and a light emitting diode having a full radiation divergence angle (after radiation divergence angle) of 8 ° or less is used. The luminous flux emitted from the light source can be suitably condensed while suppressing the angle divergence.
[0018]
  The invention described in claim 5 is described in any one of claims 1 to 4, for example, as shown in FIG. 1.Video projectorIn
  The condensing system is provided with a molded lens (for example, a concave lens 13) for shaping a light beam condensed by the condensing lens into a predetermined light beam at the time of projection.
[0019]
According to the fifth aspect of the present invention, the same effect as in the first to fourth aspects can be obtained, and the light beam condensed by the condensing lens is formed into a predetermined light beam by the molding lens at the time of projection. Can do. Therefore, for example, when the projection illumination light source device of the present invention is applied as a light source of a video projector, the projection illumination light source device can be shaped so as to have a predetermined luminous flux adapted to a projection lens that projects an image onto a screen.
As a result, vignetting of the projection illumination light flux is suppressed by the finite size of the optical system, and the radiated light from the light emitting diode can be used efficiently, which can contribute to higher brightness of the projection illumination light source. .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, with reference to FIGS. 1-6, the projection illumination light source device of embodiment of this invention is demonstrated in detail.
The projection illumination light source device of the present embodiment is used as a light source for a video projector to project a predetermined video onto the screen 19.
[0021]
[First Embodiment]
First, the configuration will be described.
As shown in FIG. 1, the entire optical system of the video projector includes a projection illumination light source device 10 according to the first embodiment and a video display element 16 that gives video information to a projection illumination light beam emitted from the projection illumination light source device 10. And the projection lens 17 for projecting the projection illumination light beam given the image information onto the screen 19 and the projection illumination light beam from the projection illumination light source device 10 to the image display element 16 and the image display element 16 It is mainly composed of a polarization beam splitter 15 that makes the projection illumination light beam receiving information incident on the projection lens 17, and the like.
[0022]
As shown in FIG. 1, the projection illumination light source device 10 includes a planar light source 11 composed of LED elements 11 a disposed on a flat surface 18 and a condensing system that condenses radiated light from the planar light source 11. A is the main component.
The condensing system A includes a convex condenser lens 12 (condenser lens), a concave lens 13 (molded lens) that molds a light flux condensed by the convex condenser lens 12 into a projection illumination light flux that satisfies necessary characteristics, and an LED. The main component is a polarization conversion element 14 that makes the radiated light from the elements 11a...
[0023]
The LED elements 11a... Are provided with RGB colors in an integrated manner on the plane 18. Then, radiated light of each RGB color is radiated from the individual LED elements 11a... Arranged discretely in this way, and the radiated light of each RGB color is mixed in a time-sharing manner to obtain a planar light source 11 of white light. It is supposed to function as. In the present embodiment, 7 × 7 (total of 49) LED elements 11a... Are provided on the plane 18. In FIG. 1, only one row (seven) of the 7 × 7 LED elements 11a.
Further, the full angle of radiation divergence of the LED elements 11a used in the first embodiment is 8 °.
[0024]
The direction of the optical axis of each LED element 11a is arranged on the plane 18 so as to be in a predetermined direction with respect to the optical axis of the convex condenser lens 12. This direction is determined depending on the distance from the optical axis of the convex condenser lens 12 to the LED elements 11a... In the present embodiment, the LED element 11a located at a position far from the optical axis of the convex condenser lens 12. It is arranged so as to face outward from the optical axis of the convex condenser lens 12 at a larger angle.
In addition, by arranging the individual LED elements 11a in an inclined manner in this way, the projection illumination light beam that illuminates the image display element 16 is prevented from spreading widely with a large angle divergence when entering the projection lens. Can do. Thereby, a projection illumination light source will be efficiently guide | induced to the projection lens 17, and high brightness can be achieved.
[0025]
In the present embodiment, the angle between the optical axis of each LED element 11a... And the optical axis of the convex condenser lens 12 is defined by the following relational expression (a).
θ = A · r (where A = π / 1800) (a)
Here, in the formula (a), r: distance from the optical axis of the convex condenser lens 12 of the LED element 11a (mm unit), θ: the optical axis of the LED element 11a ... and the optical axis of the convex condenser lens 12. An angle (in radians).
And LED element 11a ... is inclined in the outward direction which leaves | separates the LED element tip which radiates | emits light from the whole optical axis.
[0026]
When the LED elements 11a are arranged on the plane 18, the applicable relational expression is not limited to the expression (a). That is, if the angle can be determined depending on the distance from the optical axis of the convex condenser lens 12 to the LED elements 11a, and a projection illumination light beam in which the angle divergence of the projection illumination light beam is suppressed can be obtained, formula (a) Other relational expressions may be applied.
[0027]
Further, in order to arrange the LED elements 11a on the plane 18, for example, a configuration in which LEDs of RGB (three primary colors) are dispersed may be arranged, or a planar light source that emits light for each RGB color may be used. It is good also as a structure arrange | positioned so that it may provide independently. In order to obtain a white light source by combining the three primary colors, for example, in the former case, the LED elements 11a... Are arranged in a distributed manner so that the light emitted from the LED elements 11a. Just do it. In the latter case, it is preferable to provide a filter (for example, a dichroic filter) that can combine the colors.
[0028]
Further, as shown in FIG. 1, the convex condenser lens 12 is a well-known lens that condenses the radiated light from the LED elements 11a, and is arranged so that its optical axis is orthogonal to the plane 18. In this embodiment, a convex condenser lens having a diameter of 100 mm and a focal length of 144 mm is used.
The concave lens 13 shapes the projection illumination light beam from the convex condenser lens so as to be a predetermined light beam that matches the projection lens 17. Thereby, the projection illumination light beam which suppressed angle divergence can be obtained, and the emitted light from LED can be utilized efficiently. In the present embodiment, a concave lens 13 having a diameter of 40 mm and a focal length of 90 mm is used.
[0029]
The polarization conversion element 14 is a known element that aligns the projection illumination light beam formed by the concave lens 13 with a predetermined polarization component. In the present embodiment, the polarization conversion element 14 is an element that aligns randomly polarized radiation emitted from the LED elements 11a.
[0030]
Further, as shown in FIG. 1, the polarization beam splitter 15 includes a surface 15a that reflects the S-polarized component of incident light by 90 ° and transmits the P-polarized component. Therefore, when the radiated light from the LED elements 11a is aligned with the S-polarized light by the polarization conversion element 14 and enters the polarization beam splitter 15 via the surface 15b, it is reflected toward the image display element 16 by the surface 15a. It will be. As a result, a projection illumination light beam aligned with a predetermined polarized light (S-polarized light) is incident on the image display element 16.
[0031]
In this embodiment, the image display element 16 uses a well-known reflective liquid crystal display element, and has a small diagonal size of 1 inch. The image display element 16 is disposed in the vicinity of the surface 15c of the polarization beam splitter 15 and substantially parallel to the surface 15c.
When the reflected light (S-polarized light) from the polarization beam splitter 15 is incident on the image display element 16, it is reflected in the direction of the projection lens 17 at the surface side portion of the image display element 16, and at this time, the S-polarized light To P-polarized light. As a result, the light passes through the surface 15 a of the polarization beam splitter 15 and is guided to the projection lens 17.
[0032]
The projection lens 17 is a lens that projects the projection illumination light beam obtained from the image information by the image display element 16 onto the front screen 19. In the present embodiment, the projection lens 17 has a diameter of 40 mm and F2. .
[0033]
Hereinafter, with reference to FIGS. 1 and 2, a description will be given of how the emitted light of the projection illumination light source device 10 of the first embodiment travels.
First, the entire optical path of a video projector including the projection illumination light source device 10 according to the first embodiment will be described with reference to FIG.
That is, the radiated light from the LED elements 11a... Arranged at an inclination based on the formula (a) is collected by the convex condenser lens 12 and guided to the concave lens 13. Then, the concave lens 13 is shaped so as to have a predetermined projection illumination light beam, and the polarization conversion element 14 aligns it with S-polarized light.
Next, the projection illumination light beam aligned with the S-polarized light by the polarization conversion element 14 is guided to the polarization beam splitter 15. This projection illumination light beam is incident on the polarization beam splitter 15 via the surface 15b, and is reflected by 90 ° on the surface 15a of the polarization beam splitter 15 in the direction toward the image display element 16.
Next, after exiting from the polarization beam splitter 15 via the surface 15c, it is guided to the image display element 16 to provide image information. At this time, the image display element 16 reflects the light toward the projection lens 17 and changes from S-polarized light to P-polarized light. Thus, when the light is again incident on the polarization beam splitter 15 through the surface 15c, it is aligned with the P-polarized light and passes through the surface 15a to go to the projection lens 17. Then, the light is guided to the projection lens 17 through the surface 15d.
Next, the projection lens 17 projects the projection illumination light beam 1 </ b> A given the image information onto the front screen 19, and a predetermined image is projected onto the screen 19.
[0034]
Hereinafter, in the projection illumination light source device 10 according to the first embodiment, how the light travels until the radiated light from the LED elements 11a enters the projection lens 16 will be described with reference to FIG.
2 shows the optical path of the radiated light from the three LED elements 11a arranged at the middle and both ends of the LED elements 11a of one row (seven). Further, in order to illustrate the projection illumination light beam so that it can be understood in a straight line, the optical path that passes through the polarization beam splitter 15 is shown equivalently by separating the optical path before and after reflection by the image display element 16. Yes. The projection lens 17 shows only the principal point position and the aperture at the principal point position.
[0035]
As shown in FIG. 2, the emitted light from the LED element 11 a disposed at the center is condensed by the convex condenser lens 12, and then shaped to be a predetermined light beam by the concave lens 13. Aligned to S-polarized light. Next, image information of the image display element 16 is obtained via the polarization splitter 15 and is incident on the projection lens 17.
Further, the emitted light from the LED elements 11a arranged at both ends is tilted in a predetermined direction in which the optical axis of the LED elements 11a is directed outward from the optical axis of the convex condenser lens 12 based on the formula (a). Therefore, when the light is condensed in the direction facing inward by the convex condenser lens 12 and combined into one light beam by the concave molding lens 13, the optical axis of radiation from each light emitting diode is parallel to the optical axis of the entire optical system. Bent to approach. Thereby, it is suppressed that the projection illumination light flux obtained from the LED elements 11a.
[0036]
As described above, as shown in FIG. 2, the projection illumination light flux from the LED elements 11 a is kept slightly wider than the image display element 16 until it exits the concave lens 13 and enters the projection lens 17. Propagated as it is. Thereby, the radiation | emission from LED element 11a ... can be guide | induced to the projection lens 17 effectively.
That is, by arranging the LED elements 11a to be tilted based on the formula (a) as described above, the angle divergence of the projection illumination light beam guided to the projection lens 17 can be suppressed, and the projection illumination light beam having high emission luminance. Can be obtained.
[0037]
According to the projection illumination light source 10 of the first embodiment described above, using the LED with a radiation divergence full angle of 8 °, the optical axis of the LED is outside the optical axis of the convex condenser lens 12 based on the formula (a). By disposing as described above toward the projector, it is possible to obtain a projection illumination light beam that suppresses angle divergence.
Therefore, the radiated light from the LED elements 11a can be effectively guided to the projection lens 17 that projects an image, and the brightness of the projection illumination light beam can be increased. Thereby, the small image display element 16 can also be efficiently projected.
Further, from the characteristics of the light emitting diode, a long life, high efficiency, high G resistance and the like can be given to the projection illumination light source.
[0038]
In the present embodiment, a reflective liquid crystal display element is used as the image display element 16, and the polarization conversion element 14 aligns the polarized light from the LED elements 11 a. The emitted light from the LED elements 11a can be efficiently used.
[0039]
[Comparative Example 1]
Hereinafter, as Comparative Example 1, FIG. 3 shows an example in which LED elements 11a... Having a radiation divergence full angle of 8 ° are used and the optical axes of the LED elements 11a. . Therefore, FIG. 2 and FIG. 3 differ only in the arrangement method of the LED elements 11a.
Compared with the state of light traveling in FIG. 2, the projection illumination light beam after being formed by the concave lens 13 has already started to expand before entering the projection lens 17, deviating from a predetermined optical path, and used as a light source. The proportion of projected illumination light flux that cannot be increased.
That is, when the LED elements 11a... Having the same radiation divergence full angle (8 °) are used, the light incident on the projection lens 17 by tilting the optical axis of the LED elements 11a. The vignetting loss of the projected illumination light flux and the vignetting loss of the projection illumination light flux in the projection lens 17 can be suppressed, and the radiated light from the LED elements 11a can be used effectively.
[0040]
[Comparative Example 2]
Hereinafter, as Comparative Example 2, an LED element 11b... Having a radiation divergence full angle of 10 ° is used in FIG. 4 and the optical axis thereof is inclined outward with respect to the optical axis of the convex condenser lens 12 based on the formula (a). (Similar to FIG. 2). Therefore, FIG. 2 and FIG. 4 differ only in the radiation divergence full angle of the LED elements 11a.
As shown in FIG. 4, when the total radiation divergence angle of the LED elements 11a is increased to 10 °, the projection formed by the concave lens 13 even if the optical axis of each LED element 11b is tilted based on the formula (a). Of the illumination light flux, the ratio of components that are deviated from a predetermined optical path before entering the projection lens 17 and vignetting due to the finite size of the optical system is increasing.
That is, it is preferable to use an LED element 11a used in the present embodiment having a radiation divergence full angle of 8 ° or less.
[0041]
[Second Embodiment]
As shown in FIG. 5, the projection illumination light source device 20 of the second embodiment has a small-diameter convex lens 21b (radiation direction) that adjusts the direction of emitted light of the LED elements 21a ... in front of the individual LED elements 21a ... Adjusting means). Further, the LED elements 21 a are attached in such a manner that the optical axis of the LED elements 21 a is parallel to the optical axis of the convex condenser lens 12.
Except for the above points, the configuration is the same as that of the first embodiment. Therefore, in the following description, the types and attachment methods of the LED elements 21a... Will be mainly described, and the same components are denoted by the same reference numerals and the description thereof is omitted.
[0042]
As shown in FIG. 5, the small-diameter convex lens 21 b... Translates the optical axis of the small-diameter convex lens 21 b... And the optical axis of the LED element 21 a. They are staggered. The minute distance at this time is substantially proportional to the distance from the optical axis of the convex condenser lens 12 of each LED element 21a.
Thus, the radiated light from the individual LED elements 21a is adjusted to be radiated by the small-diameter convex lens 21b... At an angle that faces outward as the distance from the optical axis of the convex condenser lens 12 increases.
Then, by arranging the small-diameter convex lenses 21b as described above, the upper and lower sides of the radiated light incident on the convex condenser lens 12 are directed to the optical axis side of the convex condenser lens 12 as in the first embodiment. It is possible to obtain a projection illumination light beam that is focused on the light and suppresses the angle divergence. As a result, the brightness of the projection illumination light beam can be increased, and the projection illumination light beam can be effectively incident on the projection lens 17.
[0043]
Further, the small-diameter convex lenses 21b ... collect and emit the radiated light from the LED elements 21a ... (radiation divergence depression means). Therefore, the full angle of radiation divergence of the LED elements 21a can be narrowed, and a projection illumination light beam with reduced angle divergence can be obtained. That is, in the present embodiment, the small-diameter convex lenses 21b... Serve as a radiation direction adjusting unit and also serve as a radiation divergence depression unit.
In the second embodiment, the LED elements 21a... Have a radiation divergence full angle of 15 °. The small-diameter convex lens 21b... Narrows the divergence light from the LED elements 21a to 8 °. ing.
[0044]
Based on the above configuration, the optical path when the video projector provided with the projection illumination light source device 20 of the second embodiment projects an image is basically the same as that of the first embodiment. That is, except that the radiated light of the LED elements 21a is radiated to the outside with respect to the optical axis of the convex condenser lens 12 via the small-diameter convex lens 21b, the first embodiment. Follow a similar light path.
[0045]
Next, in the projection illumination light source device 20 of the second embodiment, the way the light travels until the projection illumination light flux from each LED element 21a enters the projection lens 17 is the radiation from the LED elements 21a ... Since the light is adjusted by the small-diameter convex lens 21b to be in a predetermined direction, basically the same as in the first embodiment.
[0046]
According to the projection illumination light source device 20 of the above second embodiment, the radiation direction from the LED elements 21a is adjusted by the small-diameter convex lens 21b, and the radiated light incident on the convex condenser lens 12 is converted into the convex condenser lens. Depending on the distance from the 12 optical axes, it can be directed outward. Therefore, the same effects as those of the projection illumination light source 10 of the first embodiment can be obtained.
[0047]
[Third Embodiment]
As shown in FIG. 6, the projection illumination light source 30 of the third embodiment is a modification of the projection illumination light source 20 of the second embodiment, and the light of the small-diameter convex lens 31b at the tip of the LED elements 31a. By tilting the axis, the optical axis of the LED elements 31a is different. The angle at which the optical axis is inclined at this time is approximately proportional to the distance from the optical axis of the convex condenser lens 12 of each LED element 31a.
Thereby, the emitted light from each LED element 31a ... is radiated | emitted by a predetermined angle by the small diameter convex lens 31b ... arrange | positioned at each front-end | tip. Therefore, after irradiating the image display element 16, it is possible to obtain a projection illumination light beam with high emission luminance that is efficiently incident on the projection lens 17 while suppressing the angular divergence of the emitted light.
[0048]
Next, in the projection illumination light source 30 of the third embodiment, the way in which the light emitted from each LED element 31a... Enters the projection lens 17 is basically the second embodiment. It becomes the same as the form.
[0049]
According to the projection illumination light source of the third embodiment described above, the same effect as that of the projection illumination light source 10 of the first embodiment can be obtained by the small-diameter convex lens 31b.
[0050]
The present invention is not limited to the above embodiment.
For example, in the present embodiment, a reflective liquid crystal display element is used as an image display element. However, the present invention is not limited to this. For example, a transmissive liquid crystal display element or a DMD (digital micromirror device) is used. It may be used.
In addition, it is needless to say that the detailed configuration, method, and the like specifically shown can be changed as appropriate without departing from the spirit of the present invention.
[0051]
【The invention's effect】
According to the first aspect of the present invention, it is possible to obtain one projection illumination light beam with reduced angular divergence from the radiated light of a plurality of light emitting diodes distributed discretely. Therefore, it is possible to increase the brightness of the projection illumination light beam, and it is possible to obtain a projection illumination light source device that can efficiently project a small image display element.
In addition, since the light emitting diode is used as the radiation light source, properties such as long life, high efficiency, and high G resistance can be imparted to the projection illumination light source device, and a maintenance-free and long-life image projector can be obtained.
[0052]
According to the second aspect of the invention, the radiation light incident on the condenser lens can be adjusted to be the same as that of the first aspect by the radiation direction adjusting means. Therefore, an effect similar to that of the first aspect can be obtained.
[0053]
According to the third aspect of the present invention, it is possible to obtain the same effect as that of the first or second aspect, and to obtain a projection illumination light beam with reduced angle divergence.
[0054]
According to the fourth aspect of the present invention, it is possible to obtain the same effect as that of the first to third aspects, and to obtain a projection illumination light beam with suppressed angle divergence.
[0055]
According to the fifth aspect of the present invention, the same effects as those of the first to fourth aspects can be obtained, and further, a projection illumination light beam with reduced angle divergence can be obtained, and the emitted light from the light emitting diode can be efficiently used. Can be used well.
[Brief description of the drawings]
FIG. 1 is a diagram showing an entire optical path of a video projector including a projection illumination light source device 10 according to a first embodiment to which the present invention is applied.
FIG. 2 is a diagram showing how light travels to a projection lens 17 of the projection illumination light source device 10 of FIG.
3 is a diagram showing how light travels to a projection lens 17 of Comparative Example 1. FIG.
4 is a diagram showing how light travels to a projection lens 17 of Comparative Example 2. FIG.
FIG. 5 is an enlarged view of a planar light source 21 of a projection illumination light source device 20 according to a second embodiment to which the present invention is applied.
FIG. 6 is an enlarged view of a planar light source 31 of a projection illumination light source device 30 according to a third embodiment to which the present invention is applied.
[Explanation of symbols]
10, 20, 30 Projection illumination light source device
11, 21, 31 Planar light source
11a, 21a, 31a LED element (light emitting diode)
12 Convex condenser lens (Condenser lens)
13 Concave lens (molded lens)
18 plane
21b, 31b Small-diameter convex lens (radiation direction adjusting means) (radiation depression angle adjusting means)
A Condensing system

Claims (5)

A planar light source discretely distributed a plurality of light emitting diodes in a plane, a projection illumination light source and a condensing system having a condensing lens whose optical axes are arranged perpendicular to the said plane Equipment ,
An image display element for providing image information to a projection illumination light beam emitted from the projection illumination light source device;
A projection lens that projects a projection illumination light beam given image information onto a screen;
A video projector configured to irradiate the projection illumination light beam onto the image display element and to make the projection illumination light beam received by the image display element enter the projection lens, and a polarizing beam splitter ,
The length in the direction orthogonal to the optical axis direction of the light emission of the planar light source is longer than the aperture of the projection lens,
At an angle which the optical axis of the light emission of the light emitting diode, is determined depending on the distance to the light - emitting diodes from the optical axis of the condenser lens, the focusing direction of the optical axis of the condenser lens An image projector characterized by being tilted toward the outside of the optical lens. A radiation direction adjusting means for adjusting a radiation direction of the light emitting diode;
2. The image projector according to claim 1, wherein an optical axis direction of light emission of at least a part of the light emitting diodes is inclined by the radiation direction adjusting means. 3. The image projector according to claim 1, further comprising a radiation divergence depression means for narrowing a full angle of radiation divergence of the light emitting diode. The image projector according to any one of claims 1 to 3, wherein a full angle of radiation divergence of the light emitting diode itself is within 8 °. 5. The molded lens according to claim 1, wherein the light collecting system is provided with a molded lens that shapes the light beam collected by the condenser lens into a predetermined light beam during projection. The video projector described.

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